Hello Neil,
For years we have used what we call "dolly blocks" or "moving blocks" patterned after the ones used on the trucks by Keyboard Carriage. These simplify loading verticals or grand skids on & off of moving dollies as well as assisting in installing or removing vertical stage dollies.
They can be used on their side for a short lift or upright (not long ways) for a higher lift. You can lift one end either by hand or using a Johnson bar (pallet Jack, lifting lever) and insert a block then lift the other end and insert a second block as seen in the picture. There are too many other uses to detail here but this allows placing the dolly under the piano and adjusting then lowering it onto the dolly and install mounting screws. (I do the two-piece Dollie's this way and it allows me access to the screwholes on the bottom to mount to the bottom board.)
These also simplify the installation of tee nuts and stove bolts through the bottom board for vertical hinge repair.
Construction is simple and I make them from 2x4 and 2x6 material. Sometimes I would put a rope handle on one end to make removal even easier (pulling it out with my foot while I lift one end of the piano.)
Height dimension isn't all that critical as long as it gives you enough room to work and is slightly (usually around 1/4") taller than your piano dolly.
Feel free to contact me if this description is as murky as I fear.
Best regards,
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Allan Gilreath, RPT
Registered Piano Technician & President
Allan Gilreath & Associates, Inc
Calhoun, GA
706-602-7667
allan@allangilreath.com -
www.allangilreath.com------------------------------